/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_cmplx_mult_cmplx_f32.c
*
* Description:	Floating-point complex-by-complex multiplication
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
* -------------------------------------------------------------------- */
#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @defgroup CmplxByCmplxMult Complex-by-Complex Multiplication
 *
 * Multiplies a complex vector by another complex vector and generates a complex result.
 * The data in the complex arrays is stored in an interleaved fashion
 * (real, imag, real, imag, ...).
 * The parameter <code>numSamples</code> represents the number of complex
 * samples processed.  The complex arrays have a total of <code>2*numSamples</code>
 * real values.
 *
 * The underlying algorithm is used:
 *
 * <pre>
 * for(n=0; n<numSamples; n++) {
 *     pDst[(2*n)+0] = pSrcA[(2*n)+0] * pSrcB[(2*n)+0] - pSrcA[(2*n)+1] * pSrcB[(2*n)+1];
 *     pDst[(2*n)+1] = pSrcA[(2*n)+0] * pSrcB[(2*n)+1] + pSrcA[(2*n)+1] * pSrcB[(2*n)+0];
 * }
 * </pre>
 *
 * There are separate functions for floating-point, Q15, and Q31 data types.
 */

/**
 * @addtogroup CmplxByCmplxMult
 * @{
 */


/**
 * @brief  Floating-point complex-by-complex multiplication
 * @param[in]  *pSrcA points to the first input vector
 * @param[in]  *pSrcB points to the second input vector
 * @param[out]  *pDst  points to the output vector
 * @param[in]  numSamples number of complex samples in each vector
 * @return none.
 */

void arm_cmplx_mult_cmplx_f32(
    float32_t* pSrcA,
    float32_t* pSrcB,
    float32_t* pDst,
    uint32_t numSamples)
{
	float32_t a1, b1, c1, d1;                      /* Temporary variables to store real and imaginary values */
	uint32_t blkCnt;                               /* loop counters */

#ifndef ARM_MATH_CM0

	/* Run the below code for Cortex-M4 and Cortex-M3 */
	float32_t a2, b2, c2, d2;                      /* Temporary variables to store real and imaginary values */
	float32_t acc1, acc2, acc3, acc4;


	/* loop Unrolling */
	blkCnt = numSamples >> 2u;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
		/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
		a1 = *pSrcA;                /* A[2 * i] */
		c1 = *pSrcB;                /* B[2 * i] */

		b1 = *(pSrcA + 1);          /* A[2 * i + 1] */
		acc1 = a1 * c1;             /* acc1 = A[2 * i] * B[2 * i] */

		a2 = *(pSrcA + 2);          /* A[2 * i + 2] */
		acc2 = (b1 * c1);           /* acc2 = A[2 * i + 1] * B[2 * i] */

		d1 = *(pSrcB + 1);          /* B[2 * i + 1] */
		c2 = *(pSrcB + 2);          /* B[2 * i + 2] */
		acc1 -= b1 * d1;            /* acc1 =      A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1] */

		d2 = *(pSrcB + 3);          /* B[2 * i + 3] */
		acc3 = a2 * c2;             /* acc3 =       A[2 * i + 2] * B[2 * i + 2] */

		b2 = *(pSrcA + 3);          /* A[2 * i + 3] */
		acc2 += (a1 * d1);          /* acc2 =      A[2 * i + 1] * B[2 * i] + A[2 * i] * B[2 * i + 1] */

		a1 = *(pSrcA + 4);          /* A[2 * i + 4] */
		acc4 = (a2 * d2);           /* acc4 =   A[2 * i + 2] * B[2 * i + 3] */

		c1 = *(pSrcB + 4);          /* B[2 * i + 4] */
		acc3 -= (b2 * d2);          /* acc3 =       A[2 * i + 2] * B[2 * i + 2] - A[2 * i + 3] * B[2 * i + 3] */
		*pDst = acc1;               /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1] */

		b1 = *(pSrcA + 5);          /* A[2 * i + 5] */
		acc4 += b2 * c2;            /* acc4 =   A[2 * i + 2] * B[2 * i + 3] + A[2 * i + 3] * B[2 * i + 2] */

		*(pDst + 1) = acc2;         /* C[2 * i + 1] = A[2 * i + 1] * B[2 * i] + A[2 * i] * B[2 * i + 1]  */
		acc1 = (a1 * c1);

		d1 = *(pSrcB + 5);
		acc2 = (b1 * c1);

		*(pDst + 2) = acc3;
		*(pDst + 3) = acc4;

		a2 = *(pSrcA + 6);
		acc1 -= (b1 * d1);

		c2 = *(pSrcB + 6);
		acc2 += (a1 * d1);

		b2 = *(pSrcA + 7);
		acc3 = (a2 * c2);

		d2 = *(pSrcB + 7);
		acc4 = (b2 * c2);

		*(pDst + 4) = acc1;
		pSrcA += 8u;

		acc3 -= (b2 * d2);
		acc4 += (a2 * d2);

		*(pDst + 5) = acc2;
		pSrcB += 8u;

		*(pDst + 6) = acc3;
		*(pDst + 7) = acc4;

		pDst += 8u;

		/* Decrement the numSamples loop counter */
		blkCnt--;
	}

	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = numSamples % 0x4u;

#else

	/* Run the below code for Cortex-M0 */
	blkCnt = numSamples;

#endif /* #ifndef ARM_MATH_CM0 */

	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
		/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
		a1 = *pSrcA++;
		b1 = *pSrcA++;
		c1 = *pSrcB++;
		d1 = *pSrcB++;

		/* store the result in the destination buffer. */
		*pDst++ = (a1 * c1) - (b1 * d1);
		*pDst++ = (a1 * d1) + (b1 * c1);

		/* Decrement the numSamples loop counter */
		blkCnt--;
	}
}

/**
 * @} end of CmplxByCmplxMult group
 */
